heroku/heroku — pull request #993 by mfine (2014-01-09 16:17:03+00:00)
Title: Extract out 'message' for `v3`

V3 errors look like:

```
{"id":"invalid_params","message":"App must be deployed before dynos can be scaled."}
```

Extract out the message field from the JSON.

https://github.com/heroku/heroku/issues/992
https://github.com/heroku/heroku/issues/987

/cc @technomancy @pedro